Use these options to specify how the date range returns results. "Exact" means that the start and end dates of descriptions returned must fall entirely within the date range entered. "Overlapping" means that any description whose start or end dates touch or overlap the target date range will be returned.

The ACE fonds covers documents on the early history and development of NATO's integrated military structure and its staff through memorandums and letters. The majority of the documents originate from its headquarters, called SHAPE, though some documents pre-date the creation of ACE and SHAPE.